Tool retainer



G. M. NELL TOOL RETAINER May 30, 1933.

Filed March 12, 1929 I INVENTOR usfave M A/el/ fin: 54 W1.

ATTORNEY.

' GUSTAVE M. HELL, OF DETROIT, MICHIGAN, COMPANY, OF NEW' YORK, N. Y., A

Patented May 3%, 1933 utter-a STTE-S PATENT orrlcE ASSIGNOR TO CHICAGO PNEUMATIGTOOL CORPORATION or NEw'JnRsnY roof. nn'rnnvnn Application filed March 12, 1929. Serial 170.348,?80.

This application retaining working tools in place upon power machines and tools. I It has particular reference to retainers of the loop type used to maintain collared working tools in operative relation f with percussive machines such as penumatic hammersand hammer drills.

One object of the invention is to provide a simple, cheaply -m'ade,light weight and effective tool retainer of the described type. Another obj set is to devise an improved method ofv attaching theretainer to the machine but which will resist deformation, displacement, and damage when'the retainer receives a par tial or a full blow of the impact member. Other Objects will be apparent from the detailed description which follows.

In order to illustrate the invention one concrete embodiment thereof is shown in the accompanying drawing, in which:

Fig. 1 is a front end elevational view of a percussive tool having the improved retainer applied thereto; I

Fig. 2 is-a left end elevational view of the parts shown in Fig. 1'; v

Fig. Sis a fragmentary sectional view substantially on the line 3-3 of Fig. 1;

Fig.4 is a fragmentary transverse sectional view of a portion of the front head of the percussive machine shown in Fig. 1 showing in cross section one of the curved grooves within which the arms of the retainer are seated when in operative position and the camming action of the walls of he grooves when the retainer is swung to inoperative or releasing position ;1 and Fig. 5 is a plan view of the retainer proper indicating the movement of the arms in relation to the recesses for the pivot ends.

In the embodiment of the invention shown in Fig. 1, the cylinder 6 of a percussive tool, such as a portable pneumatic drill, has secured thereto as by the conventional side bolts 7 a front head 8 which receives the shank 9a of a suitable working tool, such as a drill steel 9, which is provided with a'collar 9?) for limiting theprojection of shank 9a within the front head 8. The end of tool 9 receives the blows of a reciprocating impact element or piston 10. I

relates to apparatus for Fig. 1, seat insuitable 'larly inclined, are

8 at the inner ends of curved grooves 12 To prevent tool 9 from falling out of front head 8 or from being ejected-therefrom when struck by piston 10, in the event that the tool is not in contact withthe work, a retainer 11 is provided which is j formed with an open loop 110 partly to encircle drill steel 9 and to serve as an abutment for collar 9b. Retainer 11 is preferably'ofthe bent wire type, as shown, having curved side arms 11b which, tion of the retainer shown in full lines in I grooves 12 formed by parallel curved projections '13 ,of substantial extent on front head 8. Moreover, initial pivotal movement of retainer '11 to releasing position is resisted by the lack of clearance atthe bottom of sockets 14 so that the resilient retainer mustbe forcibly distorted to effect the camming action referred to abovein order to move the pivot ends out into the clearance space 14a where free swinging movement/to releasing position is'permitted. Hence the it-of the pivot ends at the base of the sockets therefor insures a cooperating retaining efiect with the resiliency of the retainer and the interfitting groove arrangement to maintain the retainer 1n operative'position inspite of the shocks and blows encountered in service. Ends 110 of the retainer are inturned towardone another and disposed generally transverse to the axis of the tool to provide pivots-upon which retainer 11 may be swungto the inoperative position shown in broken lines in Fig. 1 so as to release working tool 9. These inturned pivots 110 are inclined from the transverse toward'abutment loop 11a (Figs. 3 and 5) and sockets -or recesses 1 L therefor, simiprovided in front head and offset as regards the axis of the percussive tool.

To give retainer '11 added resiliency and resistance to shocks,

arms 11?) may be formed with coils 11d somewhere in their length but preferably adjacent and at one side of the loop portion 11a. Side arms 11?) of the retainer curve first into line with loop 11a and then outwardly to dispose pivot ends 110 in line with coils 11d. Side arms 11?) have a in the operative 'posiabutment loop 11a.

spring tension constantly urging them toward each other and hence snugly into the curved grooves 12' between the projections 13 and also urging the pivot ends 110 into sockets 14. the double purpose of holding abutment loop 11a of the retainer in alignment with the tool collar 96 and of offering resistance to movement of retainer 11 as a whole in the direction of the'arrow in F ig; 1 when to'ol collar 96 strikes or rests upon abutment loop 11a.

In order to remove or to insert a working tool, such as 9, retainer member 11 is forced or swung to the dotted line position shown in Fig. land is held in this position by frictional engagement of pivot ends 110 in sockets 14 induced by the camming action of the lower projection 13 as side arms 11?) of the retainer are forced out of grooves 12 (Fig. 4'). This camming action spreads the side arms apart and causes them to swivel about pivot ends 110 which have limitedswinging movement in socketsl l provided by the clearance recess 1405- (Fig. 3) which is made available when the pivots are part ly withdrawn as a result of the cainming ef' fect of the initial swinging movement.

By bending pivot ends 110 at an inclination in a generally forward direction, i. e. toward coils 11d and-loop 11a, a number of importantfunctions are secured. When tool collar 96 strikes loop 11a, it has a tenden'cy to drag the retainer forwardly and to dislodge the same, but the bent pivot ends 110 not only offer resistance to such move; ment but even utilizes the movement further to enter into socketsl i andthereby resist the camming apart-of the side arms 11?). The coils 11d provide a resilient connection between abutment loop'lla and the pivot ends 110 and cooperate with the curved side arms 11?) in minimizing breakage which may result when tool collar 96 repeatedly strikes It is to be noted that the inclined pivot ends 110 also assist the coils 11d and the curved arms 11b in preventing breakage of the retainer by reason of a slight bending moment.

While the invention has been herein shown and described in what is now considered to be a preferred form, it is to be understood that it is not limited to the'specific details thereof but covers all changes, modifications, A and adaptations within the scope of the appended claims.

I claim as my invention: i

1. The combination with} a portable power machine arranged to receive the-shank of a collaredflworking tool, of a retainer for the tool having aloop portion for cooperation with the collar on the tool, and cooperating means on said machine and said retainer comprising inturned ends on the latter inclined toward said loop portion and correspond- The curved grooves 12 serve,

machine having curved ingly inclined recesses therefor in said machine for producing a tighter gripping engagement between the retainer and machine when the tool collar engages said loop portion, said sockets for a portion of their extent fitting said ends sufficiently closely to resist pivotal movement of said retainer.

2. The combination with a portable power grooves on opposite sides of its forward portion terminating in inwardly directed pivot sockets, of a retainer having a part for engaging a working tool andcurved side arms extending therefrom to fit and seat in said grooves, said arms terminating in inwardly directed pivot ends projecting into said sockets, said pivot endsand cooperating sockets being inclined from a normal transverse direction and being close fitting to resist rotati-ve movement of said retainer on said pivots. j

3. The combination with a portable power machine having a front head for receiving the shank of a working tool, said head having on opposite sides of its exterior curved grooves terminating in inwardly and for wardly directed pivot sockets offset from the axis of'said head, of a retainer having a part for engaging the working tool to retain it in 's'aidhead, said retainer having curved arms extending from said part and shaped to fit and seat in said grooves, and opposed transversely extending pivot ends on said arms seated in said sockets, said pivot ends individually having an inclination from the transverse toward said loop to conform to said pivot sockets.

4. 'In' combination with a portable machine, a wire retainer formed with an abutment'loop, coils adjacent said loop but disposed at one side thereof to give resiliency to the retainer, arms extending from said coil-s in a curve into line with said loop and then outwardly again, and inwardly bent pivots on said arms having an inclination from the transverse in the direction of said coils and loop, said machine having sockets for receiving said pivots, said sockets and pivots being close fitting to resist rotative movement of the retainer about said pivots.

5. The combination with a portable power tool having a front-head arranged to receive therein the shank of a collared work tool, of a retainer for the work tool having an abutment for cooperation with the collar of the work tool and having a complete resilient coil near the abutment and having side arms with curved ends in the same plane with the side arms and having inturned pivot ends, said curved ends being mounted directly in grooves on the fronthead, said fronthead hav- 125 ing pivot sockets inclined from a perpendicular to the axis of the front head towards the retainer abutment so that in cooperating with the pivot ends when the collar of the working tool forcibly engages the retainer 139 drawn in towards the axis of the fronthead and thereby prevent the retainer as a whole being disengaged pivot sockets and from the fronthead, said ivot ends being close fitting whereby to reslst rotation of the retainer in said sockets.

Signed by me at Wayne and State March 1929.

Detroit, in the county of of Mich, this 9 day of GUSTAVE M. NELL.

CERTIFICATE OF CORRECTION.

Patent No. 1,911,844. May 30, 1933.

GUSTAVE M. NELL.

It is hereby certified that error appears in the printed specification of the abeve numbered patent requiring correction as follows: Page 1, line 7, for "pennmatic" read "pneumatic"; same page, line 64, beginning with the word "Moreover" strike all to and including "service." in line 79, and insert the same after iine 39, of page 2; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 8th day of August, A. D. 1933.

M. J. Moore.

(Seal) Acting Commissioner of Patents. 

